A telephone conference allows multiple parties, i.e., conferees or conference participants (both terms used interchangeably), to transmit audio, video, digital data or a combination of the data types to each other. This form of conference replaces a "traditional" in-person conference requiring the participants to be present in the same location.
Typically, a conference leader contacts a telecommunications service provider and reserves a conference bridge, which is a microprocessor-controlled device for interconnecting callers. This process entails reserving a certain number of telephone lines, i.e., ports, on the conference bridge at a specific date and time. The conference leader then provides an access number, such as a 1-800 number for example, to each conference participant. At the time of the conference call, each conferee dials the access number and, perhaps, an access code or a password used as an option for security reasons. Using this procedure, each conferee is connected to the same conference bridge for participating in the scheduled conference. The calls in this type of conference are known in the art as dial-in or meet-me calls.
Telecommunications service providers may also offer a dial-out conference service. This service is similar to the dial-in conference calling, which also requires a conference leader to reserve a conference bridge in advance. In contrast to dial-in calls, rather than having each conferee call into the conference bridge using a single access number and an optional access code, an operator dials each participant's telephone number at the scheduled time of the conference to connect them to the conference bridge. The operator "dials out" of the bridge using each conferee's telephone number given by the conference leader during the reservation process. When the conference participant answers the operator's call, he is connected to the conference bridge and joins the conference with other participants.
When initially offered, a dial-out conference call was only available to conferees who used telephone numbers on a standard Public Switched Telephone Network (PSTN), such as Direct Distance Dialing (DDD) or International Direct Distance Dialing (IDDD). In order for a participant to be bridged into a conference call, a conference leader had to provide a 10-digit PSTN number of that participant to the operator.
As an alternative to the above traditional type of call, a virtual private network (VPN) or virtual dialing plan (both terms used interchangeably) grew in popularity, because it allowed customers to tailor networks to their specific communications needs without the necessity of installing fixed point-to-point private lines such as Dedicated Access Lines (DALs). Similar to Private Branch Exchange (PBX), a VPN allows easy intracompany access on a more global scale than a PBX. Using a VPN which is implemented via software techniques, a multi-location customer sets up a private dialing plan on an interexchange carrier network (IXC) using only a few digits (typically from 4 to 7) to easily dial geographically scattered locations. Advantages of VPN over a DDD/IDDD number created a need to offer dial-out conference service using Virtual Private Network numbers.
To meet this need, telecommunications service providers had to install Dedicated Access Lines for connecting a conference bridge to a switching office (switch). This implementation enabled an operator to dial-out conferees' VPN numbers and connect them to the conference bridge. In order to do this, the switch must recognize the conferee's VPN dialing plan for properly routing the call. The identification of a VPN dialing plan is based on the DAL trunk group from which the dialed-out call is originated by an operator. A separate DAL is, therefore, needed to identify each customer to the switch. This requires, for example, 100 DALs for connecting a conference bridge to a switch in order to serve 100 customers. The advantages of a VPN are, therefore, immensely offset by the expense in the additional network resources.
Furthermore, due to the current business environment in which several companies are working together on joint business ventures, participants from different companies using different VPN dialing plans would like to conduct a dial-out telephone conference. This type of conference would not have all call legs on the identical VPN dialing plan. It is extremely difficult for an operator to dial-out conferees on various VPN dialing plans, because the operator must dial-out each participant on a separate DAL trunk group, or use a burdensome calling card method.
A need, therefore, exists for a conference system to establish, utilizing a single DAL trunk group, a dial-out telephone conference with conference participants who do not use the same dialing plan.